1. FIELD OF THE INVENTION
The present invention relates to a motorcycle having a power transmission device provided with a belt type continuously variable transmission and an engine suitable for use with the power transmission device.
2. Description of the Prior Art
There has conventionally been known, for example, from Japanese Utility Model Application Laid-Open (Kokai) No. 62-165471 (165471/87), a motorcycle having a power transmission device provided with a belt type continuously variable transmission having a drive pulley provided on a crankshaft and a driven pulley provided on an input shaft of a speed reduction device which pulleys are together connected by a belt. In such a conventional power transmission device for the motorcycle, a power transmission case thereof is necessary to include therein various apparatuses such as an automatic centrifugal clutch, a gear type speed reduction device, a kick starter, a cooling mechanism and the like in addition to the belt type continuously variable transmission having the pulleys. Therefore, contrary to a demand that the power transmission device should be compact, the outside dimension thereof inevitably tends to become larger. It is therefore necessary that various apparatuses including the engine are rationally arranged to thereby effectively utilize the space and form the power transmission device compactly.
Furthermore, in an engine for the motorcycle, use of a starter motor as a starting device thereof has been well known, for example, from Japanese Patent Application Laid-Open (Kokai) No. 62-289493 (289493/87). Incidentally, in the case where the engine as described is mounted on the motorcycle, there is a problem that the characteristics of the engine cannot fully be exhibited because an intake system such as a reed valve, a carburetor or the like interferes with the starting device to render a layout difficult, and freedom of designing the intake system is impaired. It has been therefore desired to rationally layout the intake system and the starting device of the engine thereby increasing the effective utilization of the space and the freedom of designing the intake system.